Reagan made a very similar joke, not to the press, but to Steven Spielberg. The ‘Berg had just shown E.T. in the White House to Raygun and a bunch of dignitaries, and afterwards Ronnie looks at him without a hint of a smile, and says “You know, I’d say there are about 4 or 5 people in this room who know just how real that picture actually is!” Everybody did a double-take and then started laughing. I’d always assumed the incident was an urban myth, but Spielberg confirmed it awhile back in an interview with aintitcoolnews. Great story.